1. Field of the Invention
The present invention relates to a movement converter for converting the reciprocating motion of a piston and the rotational motion of an input shaft to the rotational motion of an output shaft and the reciprocating motion of the piston respectively in the case of a reciprocating type combustion engine and an air compressor. More specifically, to a movement converter for use in an engine which makes an improvement in the balance of a kinematic system and attains a reduction in vibration.
2. Description of Background Art
In a conventional series type reciprocating engine and air compressor, it is known that, in order to make the rotation smooth and reduce the vibration at the same time, the rotational shaft is provided with a fly wheel and a rotational balance weight. In this case, in the series type 4-cylinder engine, for example, a primary vertical vibration, due to the inertial unbalance, which is caused once per one rotation mainly by the motion of the piston, can be reduced to nil. However, in order to take away the vibrations which take place at even times due to rolling and the like of a connecting rod, a countermeasure is the balance weight which permits the vibration to be reduced as much as possible or that a balancer having a mechanical function is provided to eliminate the vibration. In the case where the balance weight is used, since the vibration which is incurred from the engine is not transmitted, the thickness of a cylinder block is made thicker, and a complicated vibration proof structure of the engine room is provided. On the other hand, while using the balancer, it is unavoidable that the mechanism becomes complicated.
For the purpose of reducing vibrations, various proposals have been hitherto set forth to improve the balance of the engine. For example, mechanisms which attain a reduction in the vibration by means of causing an adaption of the piston to be directly and swingingly moved in a symmetrical manner with an improvement in the balance of the engine aimed at converting its motion to the rotational motion are found in the engine according to U.S. Pat. No. 2,050,603, English Sellwood type engine, A History of the Combustion Engine, P. 241, published by Sanei Shobou on Dec. 25, 1969, and the Bradshaw engine, A History of the Combustion Engine, P. 246. In the above-identified examples, circular-shaped cylinders and the pistons are disposed in a doughnut shape so that the swinging motion may directly take place, thereby converting the motion to the rotational motion. However, such a mechanism has not been placed into practical use, because there is a difficulty in processing the cylinder and the piston and a defect occurs in terms of airtightness. Furthermore, page 260 of the aforementioned A History of the Combustion Engine refers to the American Caminez-called engine. In order to improve the balance of this 4-cylinder engine, the cylinders are radially disposed and four equilateral links are used. Such an engine adopts a system in which a line contact between a roller being mounted inside the piston and a cocoon-shape causes the roller to be rolled at high speed so that a stress around the part where the roller contacts with the cam, adjacent to the area subject to an explosion, is so large that such a part is easy to wear, thus resulting in a problem that the engine in question cannot be put into practical use in terms of durability.
In addition, according to the engine shown in Pat. No. 236,540, a wobble cam plate mechanism is disclosed for converting the reciprocating motion of the piston to rotational motion in place of the swinging motion. Almost all of the motion of the piston adopts a form of an axial piston parallel to the output shaft and the structure of a joint part wherein the line motion of the piston converted to the swinging motion becomes complicated so that a problem in terms of durability is still unsolved. This results in a case of frequently needing a rotating stopper for the movable cam.